Patent Document 1 discloses a stator in which segment coils each consisting of a pair of straight portions connected with a connecting portion in a U-like shape are set in slots of a stator core, each pair of the straight portions having distal end parts protruding on an opposite side to the connecting portion, and each distal end part is twisted in a circumferential direction and joined to a straight portion of another segment coil twisted in a circumferential direction, and a method for manufacturing the stator.
For instance, when ten in-slot wire portions are mounted, distal end parts of odd-numbered in-slot wire portions from the inner circumference are twisted clockwise and distal end parts of even-numbered in-slot wire portions are twisted counterclockwise. This twist-shaping is performed for the distal end parts of the in-slot wire portions over the whole circumference. Thus, regarding one segment coil of a U phase, between its 1st and 3rd clockwise-twisted distal end parts from the inner circumference, a 2nd distal end part of an adjacent segment coil of the U phase from the inner circumference, twisted counterclockwise, is placed.
Specifically, the 1st distal end part of the U-phase one segment coil, the 2nd distal end part of the U-phase adjacent segment coil, and the 3rd distal end part of the U-phase one segment coil are arranged closely in a radial direction. The 1st distal end part of the U-phase one segment coil and the 2nd distal end part of the U-phase adjacent segment coil are joined to each other through their end faces by TIG welding. This state is illustrated as a partial plan view of a stator in FIG. 19.